Pneumatic dispatchxcarrier-separating d device



Feb. 22, 1966 MACH ETAL 3,236,475

PNEUMATIC DISPA'ICH-CARRIER-SEPARATING DEVICE Filed Sept. 9, 1963 Fl'g-2 Fig. 7

INVENTORS HORST MACH HAN$JOACHIM PTER FRANZ L/PP/TZ United States Patent3,236,475 PNEUMATIC DISPATCH-CARRIER- SEPARATING DEVICE Horst Mach,Hans-Joachim Peter, and Franz Lippitz, Berlin, Germany, assignors toInternational Standard Electric Corporation, New York, N.Y., acorporation of Delaware Filed Sept. 9, 1963, Ser. No. 307,563 Claimspriority, application Germany, Oct. 8, 1962, St 19,821 8 Claims. (Cl.243-1) The invention relates to an arrangement in pneumatic tube systemsfor separating the lead carrier of a carrier train at a receivingstation of the system or at such a point in the system where it isdesired to stop the carriers and to dispatch them individually, forexample in order to determine their spacing or to set their route insome other manner.

Our invention refers in particular to a pneumatic carrier-separatingarrangement which slows down the carrier train by regulating thecompressed air, separates the lead carrier from the train, and thenholds it for forwarding from there. Known separating arrangementsrequire a relatively high investment in adjustable valves, shut-offvalves, tubing, drive contacts, and other equipment which increase thecost of the system considerably. Such known arrangements consist ofbranches, linked by intermediate lines, at three successive points ofthe main tube. The carrier train is intercepted between the first andthe third branch and the carrier to be separated is stopped between thesecond and the third branch and further dispatched from there, whereuponthe next lead carrier takes its place. Since, once the carriers enterthat section of the tube system provided with branches, the compressedair can no longer act on them, the carrier train is slowed down.

Our invention concerns a pneumatic carrier-separating device forpneumatic tube systems whose main tube has branches connected byintermediate lines at three successive points, in which case the carriertrain to be separated is intercepted between the first and the thirdbranch and the lead carrier to be separated is stopped between thesecond and third branch and further dispatched from there. However, thedrawback of the known arrangement, that is, the high cost of such asystem which also increases maintenance and reduces reliability ofoperation is eliminated according to our invention. This is done byarranging between the second and third branch, alternately, the input oroutput of a blower or of a similar pressure/vacuum source and a valveflap in the main tube at the point of the third branch. The first branchserves to capture the initial air. The blowers blast may be reversibleand such reversal is controlled by a contact in the main tube actuatedby a carrier.

The invention and its mode of operation will now be described with theaid of the accompanying drawings, in which:

FIG. 1 shows schematically a pneumatic tube system withcarrier-separating device according to our invention; and

FIG. 2 shows a modified embodiment of FIG. 1.

Carriers in main tube 1 travel in the direction of the arrow shown inmain tube 1. The carriers first reach braking section I and immediatelythereafter lock sections II, III. At the start of section I, branch 2captures the initial air and may have a back-pressure valve 3 and anadjustable butterfly valve 4a. In the example according to FIG. 1,branch 2 is connected to blower G. Branch 5 at the start of lock sectionII branches off from main tube 1 and has an adjustable butterfly valve4b, connected to the same side of blower G as is branch 2. The other3,236,475 Patented Feb. 22, 1966 side of blower G connects via branchtube 6 to the end of lock section III in main tube 1. Valve flap 7 isbetween II and III and can be opened in the direction of travel only bya reversed air current and otherwise remains closed due to the differentair pressures. Valve flap 7 can also be held shut by a spring. Anothervalve flap 8 may be arranged beyond branch 6 to isolate the separatingsections from the rest of the system. Main tube contact 9 serves toindicate that a carrier is in front of valve flap 7.

Such an arrangement operates as follows:

An approaching carrier or carrier train moves in the direction of thearrow into braking section I, which is shown as an upward curving arebut may also be a straight line. The carrier train reaches branch 5.Butterfly valves 4a and 4b are so adjusted that the carriers enteringsection -I are braked so that the lead carrier arrives at flap valve 7at a very low velocity. Valve flap 7 is spaced the length of one carrieraway from branch 5. The air driving the carriers is split up by branches1 and 2, so that a substantial portion travels through branch 2, andanother portion through branch 5, to blower G. The arriving carriers donot have enough kinetic energy to open valve flap 7.

When there is a carrier in front of valve flap 7, it causes main tubecontact 9 to operate. If the lead carrier of the train is to be furtherdispatched, the direction of the airflow is reversed. Whereas the airwas previously flowing in the direction of heavy arrows 10 and 11, oncereversed it flows in the direction of broken arrows :12 and 13.Back-pressure valve 3 prevents the air from escaping through branch 2.The full air current is thus directed through branch 5 and strikesbetween the lead carrier and the carriers behind it, pushing the leadcarrier through valve flap 7. Valve flap 8 prevents any inflow of airfrom the tube section ahead. With proper air conditions, it is possibleto eliminate flap valve 8. A timing circuit now stops the reversal ofairflow and the lead carrier in front of valve 8 can continue on itsway, while the rest of the carrier train is so advanced that anothersingle carrier is in front of valve 7, whereupon the process repeatsitself.

It is noteworthy that the only control such a carrierseparating devicerequires is the reversal of the blowers airflow and the removal of sucha reversal by means of a timing circuit. Flap valves 7 and 8 andbackpressure valve 3 require no external control, and butterfly valves4a and 4b are permanently set.

FIG. 2 shows a modification of the embodiment according to FIG. 1.Branch 2 with butterfly valve 4a is under vacuum or at atmosphericpressure, while another branch 14 with a butterfly valve 15' behindvalve flap 8 is at atmospheric or higher pressure. The advantage of thisarrangement is that the carriers in the main tube, when passing beyondthe locks, are not stopped by the process of separation as in theconfiguration of FIG. 1 but retain a portion of their original speed inthe conveying section due to the combined action of blower 16 in branch2 and the source of higher pressure in branch 14. In such anarrangement, flap 8 is necessary to prevent the higher pressure in theforwarding tube from having access to section III of the lock.Otherwise, this system functions similarly to that of FIG. 1.

While we have described the principles of our invention in connectionwith specific apparatus, it is to be clearly understood that thisdescription is made only by way of example and not as a limitation tothe scope of our invention as set forth in the accompanying claims.

We claim:

1. An arrangement for separating a train of carriers propelled by anair-pressure differential in the forwarding tube of a pneumatic tubesystem comprising: first, second, and third branch tubes positioned sothat carriers arrive at said first branch tube before arrivingsuccessively at said second and third branch tubes, and at said secondbranch tube before said third branch tube, said first branch operatingto relieve the pressure differential across the lead carrier of saidtrain; a reversible blower connected between said second and thirdbranch tubes, control means cooperating with air propelled by saidblower in a first direction for stopping arriving carriers between saidsecond and third tubes, and cooperating with air propelled by saidblower in a direction opposite to said first direction for moving thelead carrier of the stopped carriers between said second and third tubeswhereby only said lead carrier is in a position for further conveyancein said forwarding tube beyond the intersection of said third branchtube with said forwarding tube.

2. An arrangement according to claim 1 further comprising a fourthbranch tube connected to said forwarding tube beyond said third branchtube relative to the direction of travel of the carriers, a blower otherthan said reversible blower connected between said first and fourthbranch tubes, and a valve fla-p in said forwarding tube between saidthird and fourth branch tubes.

3. An arrangement according to claim 1 wherein said reversible blower isconnected to said first branch tube via said second branch tube.

4. An arrangement according to claim 3 wherein said control meanscomprises a first valve flap positioned in said forwarding tube betweensaid second and third branch tubes about one carrier length of thecarriers used in the pneumatic tube system away from said second branchtube.

5. An arrangement according to claim 4 wherein said control meansfurther comprises a check valve in said first branch tube for preventingair from said reversible blower, opposite to the air flow in saidpneumatic tube system, from reaching said pneumatic tube system.

6. An arrangement according to claim 5 wherein said control meansfurther comprises sensing means in said forwarding tube positionedbetween said second branch tube and said first valve flap for indicatingthe presence of a carrier between said second branch tube and said firstvalve flap.

7. An arrangement according to claim 6 wherein said control meansfurther comprises a second valve flap positioned beyond said thirdbranch tube in the direction of travel of said carriers forpneumatically separating said isolating arrangement from the pneumatictube system beyond said third branch tube when desired.

8. An arrangement according to claim 1 wherein said forwarding tube isdisposed in a horizontal position at the point of connection with saidfirst branch tube and in a vertical position at the points of connectionwith said second and third branch tubes.

No references cited.

SAMUEL F COLEMAN, Primary Examiner.

ANDRES H. NIELSEN, Examiner.

1. AN ARRANGEMENT FOR SEPARATING A TRAIN OF CARRIERS PROPELLED BY ANAIR-PRESSURE DIFFERENTIAL IN THE FORWARDING TUBE OF A PNEUMATIC TUBESYSTEM COMPRISING: FIRST, SECOND, AND THIRD BRANCH TUBES POSITIONED SOTHAT CARRIERS ARRIVE AT SAID FIRST BRANCH TUBE BEFORE ARRIVINGSUCCESSIVELY AT SAID SECOND AND THRID BRANCH TUBES, AND AT SAID SECONDBRANCH TUBE BEFORE SAID THIRD BRANCH TUBE, SAID FIRST BRANCH OPERATINGTO RELIEVE THE PRESSURE DIFFERENTIAL ACROSS THE LEAD CARRIER OF SAIDTRAIN; A REVERSIBLE BLOWER CONNECTED BETWEEN SAID SECOND AND THIRDBRANCH TUBES, CONTROL MEANS COOPERATING WITH AIR PROPELLED BY SAID BLOW-